Fluid operated servomotor



N 1944. e. E. ARMINGTON 2,362,339

FLUID OPERATED SERVOMOTOR Filed April 28, 1945 v INVENTOR. 65026 E ARM/NGTpN ATTORNEYS Patented Nov. 7, 1944 UNITED STATES PATENT OFFICE ....SZT;'..I.TZ;Z?Z..ZZZ;ZTZ;ZZ...-

or to The Euclid Road Machinery Ohio, a corporation of Ohio 00., Euclid,

3 Claims.

This invention relates to improvements in servomotor-operated check valve mechanism for controlling the fiow'to and from hydraulic jacks and the like. An object of the present invention is to provide a compact valve mechanism having a small number of parts and adapted for easy manufacture and installation .and' adapted to control flow in two directions to hydraulic jacks, rams and other devices of a similar nature.

One of the objects of the present invention is to provide in combination a double-acting hydraulic device, a main control valve for operating the device in opposite directions, and a device having two ball check valves and suitably arranged passageways, together with an actuator for a ball check in one passageway operated by fluid flow in another passageway, the result of the entire arrangement being such that the mere direction of flow through the device automatically sets the valves so that all of the fluid moves in the proper direction, and the setting of the main valve in a neutral position prevents drifting of the hydraulic device.

Other objects and advantages of the present invention will be apparent from the accompanying drawing and specification and the essential features thereof will be set-forth in the appended claims.

In the drawing, Figs. 1 and 2 are somewhat diagrammatic views showing my improved check valve arrangement in a typical installation where a pump supplies fluid under pressure for operating a double acting ram or jack, Fig. 1 showing the parts set for operating the jack in one direction, and Fig. 2 showing the parts setto operate the jack in the opposite direction. Fig. 3 is a view showing the holding position of one of the valves of Figs. 1 and 2,.

Referring to Fig. 1, a single small valve body it is provided with flow passageways Ii and i2.

In the passageway ii is a ball check valve i3 In the passageway i2 there is arranged a piston I 20 which is a snug sliding fit in the passageway --l 2. This piston is provided with a stem 20a which extends through a substantially liquid-tight opening 2i in the valve body which permits the stem to extend into the passageway l I for engagement with the ball check l3. In the position of the parts shown in-' Fig. 1, the spring l4 acting through the ball l3 has moved the piston 20 toward the left so as to close'the port l2a. This movement of piston 20 toward the left is limited by a stop pin 22 which is held in position by the plug 23. There is provided a by-pass 24 around the passageway i2 and in this by-pass is the ball check 25 which is normally urged by the spring 26 to closed position shown in dot-dash lines in Fig. 1 against the seat 25a. A stop pin 21a is'an integral portion of the plug 21 which closes one of the openings by which the by-pass 24 is originally bored out.

To illustrate how my check valve device opcrates, I have shown it connected in a system wherein a pump 28 provides a flow of pressure fluid through a control valve 29 to operate the hydraulic jack 30. This jack is provided with a reciprocable piston 3i having a piston rod 32 connected to the device to be operated. Conduits 33 and 34 connect the pump with the control valve, conduit 35 connects the control valve with a the passageway ll of valve body In, conduit 36 connects the control valve with the passageway [2 of the valve body l0, conduit I9 connects the passageway II with the right hand end of jack 30 and conduit 31 connects passageway i2 with the left hand end of jack 30.

With the control valve 25 set in the position of Fig. 1, my device operates as follows: Pressure fluid flows from the pump 28 through conduit 33, valve 29 and conduit 35 to the passageway I I. The pressure of the fluid lifts the ball l3 from its seat, whereupon the fluid flows through conduit l9 to the jack 30 and exerts pressure against the right-hand face of piston 3|. The piston then moves toward the left, causing the hydraulic liquid to flow away from the left-hand end of jack 30 through conduit 31 to the valve body. There it raises ball check, 25 from its seat as shown in full lines in Fig.1, whereupon the liquid flows through the by-pass 24 to the passageway I2, then through conduit 36, valve 29 and conduit 34 back to the pump.

When valve 29 is turned to the position of Fig.

2, flow occurs in the opposite direction as follows: From pump 28 the flow is through conduit 33, valve 29, conduit 36 and passageway i2 against the left-hand face of piston 20. The piston is thus moved from the position of Fig. 1 to that of Fig. 2, opening the port I 2a.- The stem 20a oi. the piston engages ball check l3 and holds the same away from its seat as shown in Fig. 2. .The liquid then flows through conduit 31 in this "hold" position the passageways of valve 2! connect conduits 83 and 34 so that the flow from the pump 28 is through the valve 29 and directly back to the pump. Since the valve 29' may be made a little loose in order to operate ireely, there may be a slight leakage through this valve is the hold position ot Fig. 3. In this case, if it is desired to hold a load positively against drifting, the load should be held so that the piston 3| would move toward the right if any drifting occurred. This will force ball check I! to its seat and thus efiectually prevent drifting.

It will thus be seen that I have provided a very simple device for producing the same result which heretofore has been accomplished by much more complicated devices. Furthermore, nothing is necessary to connect the valve body ill in a hydraulic system except to connect the conduits i9, 35, and 31 to the suitable openings in the valve body Hi. My improved device has only a few moving parts and is cheap to manufacture and simple to assemble.

What I claim is:

1. Valve means comprising a singl valve body provided with two openings for the connection of a first supply line, there being a first passageway in said body communicating between said openings, a check valve in said passageway normally permitting flow in said passageway in one direction only, said valve body being providedwith two other openings for the connection of a I second supply line, there being a pair of pas sageways in said body communicating in parallel between said two other openings, 9. check valve in one of said pair of passageways permitting flow in said second supply line therethrough in one direction only, there being an expansible chamber device in the other of said pair of passageways movable by fluid flow in said second supply line in th opposite direction, and means extending from said device into said first passageascaaae way for opening said first named check valve upon said movement of said device.

2. Valve means comprising a single valve body provided with two openings for the connection of a first supply line, there being a first passageway in said body communicating between said openings, at check valve in said passageway normally permitting flow in said passageway in one direction only, spring means urging said valve toward its seat, said valve body being provided with two other openings for the connection of a second supply line, there being a pair of passageways in said body communicating in parallel between said two other openings, one of said pair of passageways providing a cylinder in axial alinement with said check valve, a piston fitted in said cylinder, said piston having a stem extending through a substantially leak-proof bore in said body into said first passageway and engaging said check valve, there being a port in said cylinder forming part of said one of said pair of passageways, said piston normally closing said port to flow through said one of saidpair of passageways when said valve is closed, said piston being movable by fluid flow in said second supply line in one'direction to open said valve and to open said port to said flow, and a check valve in the other of said pair of passageways permitting fiow in said second supply line in the opposite direction only.

3. Valve means comprising a single valve body provided with two openings for the connection of.a first supp y line, there being a first passageway in said body communicating between said openings, a check valve in said passageway normally permitting flow in said passageway in one direction only, said valve bod being provided with two other openings for the connection of a second supply line, there being a pair of passageways in said body communicating in parallel between said two other openings, a check valve in one of said pair of passageways permitting flow in said second supply line therethrough in one direction only, there being an expansible chamber device responsive to flow in the other of said pair of passageways and movable by fluid flow in said second supply line in the opposite direction, and an operative connection between said device and said first-named check valve for opening the latter by said movement oi. said device.

GEORGE E. ARMINGTON. 

